The present invention relates to a lead wire mounting structure for an electroluminescence adapted to be used by fixedly connecting its terminals to insulated lead wires.
A dispersion type electroluminescence (which will be hereinafter referred to as EL) is widely used as a back-light for a liquid crystal display since it is manufactured at a low cost and can exhibit a high luminance.
FIG. 2 shows a sectional view of the EL as mentioned above. Referring to FIG. 2, reference numeral 1 generally designates an EL composed of an EL element 3 disposed on a reinforcing plate 2, a pair of sealing films 4 and 5 for sealing the EL element 3, and a pair of flat terminals 6 and 7 projecting outside between the sealing films 4 and 5 heat-sealed. The EL element is formed by laminating a transparent sheet 9 on which a transparent electrode 8 is formed, a light emitting layer 10 formed by dispersing a phosphor in an organic binder, and a counter electrode 11 formed of metal foil of the like. The terminals 6 and 7 are lead out from the transparent electrode 8 and the counter electrode 11.
When the terminals 6 and 7 are connected to an AC power supply to apply a predetermined voltage between the electrodes 8 and 11, the light emitting layer 10 is operated to emit light, and the light is transmitted through the sealing film 4 having a light transmissivity to the outside.
In the case that a position of installation of the EL 1 into an equipment such as a liquid crystal display is at a distance from the power supply, the terminals 6 and 7 are required to be electrically connected through long insulated lead wires to the power supply. Conventionally, reliable connection of the insulated lead wires to the EL has been established by the construction as shown in FIG. 3. Referring to FIG. 3, the sealing films 4 and 5 of the EL 1 are formed to project at portions where the terminals 6 and 7 project. After the terminals 6 and 7 are soldered to bare end portions of insulated lead wires 15 and 16, a pair of heat-shrinkage resin tubes 17 and 18 are provided to cover connecting areas extending from the projecting portions of the sealing films 4 and 5 to insulated end portions of the insulated lead wires 15 and 16, respectively. Then, the resin tubes 17 and 18 are heated to be shrunk.
However, the above-mentioned construction has the following problems. First, prior to soldering the bare end portions of the insulated lead wires 15 and 16 to the terminals 6 and 7, the resin tubes 17 and 18 surrounding the insulated lead wires 15 and 16 must be isolated from the soldering portions, and after the soldering, they must be moved to a predetermined position where the connecting areas are covered with the resin tubes 15 and 16. Thus, it is troublesome to handle the resin tubes 17 and 18 which are small, causing a deterioration of workability. Secondly, the projecting portions of the sealing films 4 and 5 to be covered with the resin tubes 17 and 18 are weak in strength, resulting that stress concentration is generated at the bases of the projecting portions. Accordingly, there is a possibility that the projecting portions of the sealing films 4 and 5 will be cracked or separated and that the terminals 6 and 7 will be broken.